Synthesis of a new NIR fluorescent Nd complex labeling agent.

Fluorescent analysis has been widely used in biological, chemical and analytical research. A useful fluorescent labeling agent should include NIR emission, a large Stoke's shift, and good labeling ability without interfering with the pharmacological profile of the labeled compound. Thus, we planned to develop an M-AMF-DOTA(Nd) derivative composed of an NIR fluorescent moiety and a maleimide conjugating moiety as a new NIR fluorescent labeling agent which fulfills these requirements. M-AMF-DOTA(Nd) was synthesized from 4-amino-fluorescein and was conjugated with an avidin molecule (Avidin-AMF-DOTA(Nd)) through Lys-side chains by reaction with 2-iminothiolane. The fluorescent features of M-AMF-DOTA(Nd) and Avidin-AMF-DOTA(Nd) were comparatively evaluated. A binding assay of Avidin-AMF-DOTA(Nd) with D-biotin and a tumor cell-uptake study were performed to estimate the effects of conjugation on the biological and physicochemical features of the protein. M-AMF-DOTA(Nd) was obtained in 22% overall yield. M-AMF-DOTA(Nd) had a typical NIR fluorescence from the Nd ion (880 nm and 900 nm from 488 nm excitation). Avidin-AMF-DOTA(Nd) was easily synthesized and also had typical NIR fluorescence from the Nd ion without loss of fluorescent intensity. The binding affinity of Avidin-AMF-DOTA(Nd) to D-biotin was equivalent to naive avidin. Avidin-AMF-DOTA(Nd) was taken up by tumor cells in the same manner as avidin conjugated with fluorescein isothiocyanate, an established, widely used fluorescent avidin. Results from this study indicate that M-AMF-DOTA(Nd) is a potential labeling agent for routine NIR fluorescent analysis

Versatile Photorearrangement of Photocycloadducts from 5-Fluoro-1,3-dimethyluracil and Naphthalene

Direct UV-irradiation of 5-fluoro-1,3-dimethyluracil (5-FDMU) and naphthalene (1) with a 500 W high-pressure mercury lamp in a degassed Pyrex tube (λ > 300 nm) predominantly afforded benzopyrimidobarrelene derivative (2) through 1,4-addition, while irradiation in the presence of piperylene in singlet excited states preferentially afforded naphthocyclobuta-pyrimidine derivative (3) via 1,2-addition. Upon 254 nm light-irradiation of 2 gave rise to the formation of benzopyrimidosemibullvalene (4) in fair yields. The reaction pathway for the formation of 4 is reasonably explained in the terms of di-π-methane rearrangement. Adduct 3 was newly converted to the corresponding barrelene derivative (2) by long-wave-length irradiation in the presence of a triplet sensitizer

Isolation and identification of new vasodilative substances in diesel exhaust particles

Goal, Scope, and Background: We recently developed a new isolation method for diesel exhaust particles (DEP), involving successive extraction with H2O, sodium bicarbonate, and sodium hydroxide, in which the sodium hydroxide extract was found to consist of phenolic components. Analysis of the extract revealed that vasodilative active nitrophenols are in DEP in significantly higher concentration than those estimated by an earlier method involving a combination of solvent extraction and repeated chromatography. These findings indicated that our new procedure offers a simple, efficient and reliable method for the isolation and identification of bioactive substances in DEP. This encouraged us to extend our work to investigating new vasodilatory substances in the sodium bicarbonate extract. Materials and Methods: DEP were collected from the exhaust of a 4JB1-type engine (ISUZU Automobile Co., Tokyo, Japan). GC-MS analysis was performed with a GCMS-QP2010 instrument (Shimadzu, Kyoto, Japan). Results: DEP dissolved in 1-butanol was successively extracted with water, sodium bicarbonate, and then aqueous sodium hydroxide. The sodium bicarbonate extract was neutralized and the resulting mixture of acidic components was subjected to reverse-phase (RP) column chromatography followed by RP-HPLC with fractions assayed for vasodilative activity. This led to the identification of terephthalic acid, p-hydroxybenzoic acid, isophthalic acid, phthalic acid, 3-hydroxy-4-nitrobenzoic acid, 4-hydroxy-3-nitrophenol, and 1,4,5-naphthalene tricarboxylic acid as components of DEP. Discussion: The sodium bicarbonate extract was rich in the acidic components. Repeated reverse-phase chromatography resulted in the successful isolation of several acidic substances including the new vasodilative materials, 4-hydroxy-3-nitrobenzoic acid, and 3-hydroxy-4-nitrobenzoic acid. Conclusion: Our new fractionation method for DEP has made possible the isolation of new vasodilative compounds from the sodium bicarbonate extract

An experimental approach to study the biosynthesis of brominated metabolites by the red algal genus Laurencia

The production of labeled brominated metabolites with radioactive 82Br in Laurencia species was investigated as part of a study of the biosynthesis of halogenated metabolites from species belonging to the red algal genus Laurencia (Rhodomelaceae, Ceramiales). Radiobromide [82Br], thin-layer chromatography (TLC), and TLC-autoradioluminography (ARLG) were used. When cultured in artificial seawater medium (ASP12NTA including Na82Br) under 16:8 h light:dark (LD) illumination cycles for 24 h, each of the strains of Laurencia, Laurencia japonensis Abe et Masuda, Laurencia nipponica Yamada (laurencin-producing race and laureatin-producing race), and Laurencia okamurae Yamada, produced species- (or race-) specific 82Br-containing metabolites. In the case of the laurencin-producing race of L. nipponica, laurencin and deacetyllaurencin were found to be produced in approximately 1:1 ratio, though laurencin is the major metabolite in the wild sample. Furthermore, when cultured in the dark, the production rates of brominated metabolites in Laurencia spp. were found to be diminished. The present study strongly indicates that the use of radiobromine [82Br] in combination with the TLC-ARLG method is an effective approach for investigating the biosynthesis of brominated metabolites in Laurencia

Usefulness of 11C-Methionine for Differentiating Tumors from Granulomas in Experimental Rat Models: A Comparison with 18F-FDG and 18F-FLT

Many clinical PET studies have shown that increased 18F-FDG uptake is not specific to malignant tumors. 18F-FDG is also taken up in inflammatory lesions, particularly in granulomatous lesions such as sarcoidosis or active inflammatory processes after chemoradiotherapy, making it difficult to differentiate malignant tumors from benign lesions, and is the main source of falsepositive 18F-FDG PET findings in oncology. These problems may be overcome by multitracer studies using 39-deoxy- 39-18F-fluorothymidine (18F-FLT) or L-11C-methionine. However, 18F-FLT or 11C-methionine uptake in granulomatous lesions remains unclarified. In this study, the potentials of 18F-FLT and 11C-methionine in differentiating malignant tumors from granulomaswere comparedwith 18F-FDGusing experimental ratmodels. Methods: Dual-tracer tissue distribution studies using 18F-FDG and 3H-FLT (groups I and III) or 18F-FDG and 14C-methionine (groups II and IV)were performed on rats bearing both granulomas (Mycobacterium bovis bacillus Calmette-Gue´ rin [BCG]–induced) and hepatomas (KDH-8–induced) (groups I and II) or on rats bearing both turpentine oil–induced inflammation and hepatomas (groups III and IV). One hour after the injection of a mixture of 18F-FDG and 3H-FLT or of 18F-FDG and 14C-methionine, tissues were excised to determine the radioactivities of 18F-FDG, 3H-FLT, and 14C-methionine (differential uptake ratio). Results: Mature epithelioid cell granuloma formation and massive lymphocyte infiltration were observed in the granuloma tissue induced by BCG, histologically similar to sarcoidosis. The granulomas showed high 18F-FDG uptake comparable to that in the hepatomas (group I, 8.18 6 2.40 vs. 9.13 6 1.52, P 5 NS; group II, 8.43 6 1.45 vs. 8.91 6 2.32, P 5 NS). 14C-Methionine uptake in the granuloma was significantly lower than that in the hepatoma (1.31 6 0.22 vs. 2.47 6 0.60, P , 0.01), whereas 3H-FLT uptake in the granuloma was comparable to that in the hepatoma (1.98 6 0.70 vs. 2.30 6 0.67, P 5 NS). Mean uptake of 18F-FDG, 3H-FLT, and 14C-methionine was markedly lower in the turpentine oil–induced inflammation than in the tumor. Conclusion: 14C-Methionine uptake was significantly lower in the granuloma than in the tumor, whereas 18F-FDG and 3H-FLT were not able to differentiate granulomas from tumors. These results suggest that 14C-methionine has the potential to accurately differentiate malignant tumors frombenign lesions, particularly granulomatous lesions, providing a biologic basis for clinical PET studies